JPH032881B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a cellulose derivative obtained by carboxymethylating the surface of microcrystalline cellulose and a method for producing the same. The microcrystalline cellulose referred to here is finely powdered cellulose obtained by subjecting cellulose raw materials such as pulp, linter, and cotton to acid hydrolysis, washing and removing amorphous regions, and then grinding, refining, and drying. , usually a powder with a particle size of 100μ or less. Microcrystalline cellulose is used for various purposes due to its characteristics such as moldability, dispersion/suspension stability, thixotropy, physiological harmlessness, tasteless, odorless, and colorless properties. That is, it is used in pharmaceutical excipients, super-aids, food additives, dispersants, viscosity modifiers, and the like. In particular, the function of foods as low-calorie bulking agents is becoming more important. However, microcrystalline cellulose alone is not practically sufficient as an emulsion suspension stabilizer or thickener for sols, gels, and colloids, and a water-soluble polymer must be used in combination. In addition, since microcrystalline cellulose has a unpleasant texture, the amount added is limited, or microcrystalline cellulose is used in combination with a water-soluble polymer or coated with a water-soluble polymer (Japanese Patent Application Laid-Open No. 1983-1999-1). 72868, 1978-157875, 1978 Japanese Patent Publication
−34006 etc.). Combined use with these water-soluble polymers,
Alternatively, even if a coated product is used, it is difficult to use because the taste is insufficient or the viscosity increases too much and fluidity is lost. The present invention increases dispersion/suspension stability by carboxymethylating only the surface layer of microcrystalline cellulose, while imparting smooth texture to the microcrystalline cellulose, making it suitable as a food additive. The goal is to discover what can be done. A method of carboxymethylating the surface of microcrystalline cellulose and the application of the product to a sizing agent for textiles are disclosed in Japanese Patent Publication No. 19438/1983. The specification describes a method of obtaining carboxymethylated microcrystalline cellulose by treating microcrystalline cellulose with an aqueous sodium hydroxide solution using water as a medium and adding an aqueous monochloroacetic acid solution. However, the carboxymethylated microcrystalline cellulose produced in this way has properties such as film-forming properties and alkali solubility, and is rather similar to carboxymethylcellulose. It is unsuitable for applications such as agents. Special Public Service 1977-
19438 mainly introduces carboxymethyl groups onto the surface of microcrystalline cellulose, but with this method, etherification still penetrates slightly into the inside. In order to convert microcrystalline cellulose into carboxymethyl ether without changing its properties, it is necessary to limit the reaction to only the very surface layer. As a result of extensive research, the present inventors found that a slurry method using an organic solvent as a reaction medium was used to carboxymethyl etherify only the very surface layer of microcrystalline cellulose, and the amount of water in the reaction system was extremely small. By using it within a limited range, we succeeded in obtaining the desired microcrystalline cellulose derivative. That is, the present invention is a manufacturing method in which monochloroacetic acid is dissolved in an aliphatic alcohol/water mixed solvent, then microcrystalline cellulose is added to form a slurry, and sodium hydroxide is added to etherify the mixture.
By keeping the concentration of water in the mixed solvent at 5% or less, the reaction can be carried out while suppressing swelling and internal penetration during alcelization, and the degree of etherification can be maintained at 0.05 to 0.05 as a whole.
0.8, and a method for producing the same. The microcrystalline cellulose derivative of the present invention can be used as an excipient, suspension stabilizer, food additive, etc., and has improved dispersion stability, shape retention, texture, etc. compared to the raw material microcrystalline cellulose. It is something that Suitable applications for the microcrystalline cellulose derivative of the present invention include, for example, excipients for dry tableting, ice cream, mayonnaise, salad dressings, bread, cosmetic creams, and cosmetic emulsions. The present invention will be explained below with reference to Examples. The degree of etherification, average particle size as a powder, fluidity, and dispersibility in water were tested and quantified by the following methods. 1 Degree of etherification (DS) Accurately weigh 1 g of the dry sample, wrap it in quantitative paper, place it in a platinum crucible or porcelain crucible, heat it gently to carbonize it, then ash it at a temperature not exceeding 600℃, and then cool it. Transfer the crucible to a 500 ml beaker, add about 250 ml of water, then add exactly 50 ml of N/10H ₂ SO ₄ and boil for 30 minutes. It is cooled, phenolphthalein indicator is added and excess acid is titrated with N/10N _a OH solution. Perform a blank test in the same manner, and determine the degree of etherification using the following formula. A = (B-S) x F/dry sample g-alkalinity Note 1 Degree of etherification (mol) = 162 x A/10000-80A B: N/10N required for blank test Amount of _a OH used (ml) S: Actual test 〃 F: Potency of N/10N _a OH solution Note) How to determine alkalinity Accurately weigh approximately 1 g of the dry sample and dissolve it by adding approximately 200 ml of water. Accurately add 5 ml of N/10H ₂ SO ₄ and boil for 10 minutes. After cooling, add a phenolphthalein indicator and titrate with N/10N _a OH. Alkalinity = 5F'-N/10N _a Number of OH (ml) x F/g dry sample F: N/10N _a Potency of OH solution F': N/10H ₂ SO ₄ 〃 2 Average particle size Dry sieving method Median diameter 3 Flowability index Powder tester (manufactured by Hosokawa Powder Engineering Institute Co., Ltd.)
The loosened apparent specific gravity, hardened apparent specific gravity, angle of repose, angle of spatula, and particle size distribution are measured using the , and the values are comprehensively converted into an index. The larger the value, the better the fluidity. (Reference material) "Flow characteristic test of powder and granular material using powder tester and its application" Yokoyama Tohei Co., Ltd. Hosokawa Powder Technology Research Institute June 3, 1976, Powder Industry Lecture (No. 1) sponsored by the Japan Powder Industry Association 23 times) 4 Dispersibility in water Take 30 g of a dry sample, add 270 ml of water, mix at high speed (more than 8000 revolutions per minute) for 5 minutes, and then
ml into a 100 ml graduated cylinder, and after standing for 6 hours, measure the thickness of the supernatant liquid, and calculate the thickness of the dispersed layer by 100 ml.
Converted as . Therefore, the smaller the numerical value, the better the dispersibility. Production example of microcrystalline cellulose Commercially available sulfite wood pulp is shredded and hydrolyzed in a 0.5% hydrochloric acid solution at 125°C for 1 hour. The resulting acid-insoluble residue is neutralized and washed, and the resulting pulp is ground. Spray dried. The dried product was passed through a 35-mesh sieve to remove coarse materials, yielding white microcrystalline cellulose A having an average particle size of 65 μm, a degree of polymerization of 200, and a degree of crystallinity of 75. The infrared absorption spectrum of the obtained microcrystalline cellulose A is shown in FIG. Comparative Example 1 Microcrystalline cellulose A obtained in Production Example was carboxymethylated using an isopropanol/water mixed solvent under known conditions to obtain a uniform etherification reaction product. 100 g of microcrystalline cellulose A was placed in a mixed solution system of 1180 g of isopropanol (IPA), 100 g of water, and 40 g of _NaOH , and the mixture was stirred at room temperature for 90 minutes. Add 60g of 50% monochloroacetic acid (MCA) to this slurry system in IPA.
After stirring at room temperature for 30 minutes, raise the temperature to 60℃,
It continued for 2 hours. After the reaction was completed, the solid content was washed with a 75% aqueous methanol solution, replaced with ethanol, and then dried. The obtained white fine powder is designated as B. The infrared absorption spectrum of B is shown in FIG. Examples 1 to 5 and Comparative Example 2 Microcrystalline cellulose A obtained in the production example,
Carboxymethylation was carried out using an IPA/water mixed solvent with a small amount of water. Dissolve the specified amount of water and monochloroacetic acid (MCA) in 1180g of isopropanol (IPA), then
Add 100g of A to make a slurry. A predetermined amount of sodium hydroxide (N _a OH) was added little by little in the form of granules to this slurry system while stirring, and then the temperature was raised to cause a reaction. After the reaction was completed, the solid content was washed with a 75% aqueous methanol solution, replaced with ethanol, and then dried. The reaction conditions are shown in Table 1, and the degree of etherification and other physical property measurements are shown in Table 2. Moreover, Example-2,
The infrared absorption spectra of the 4 products are shown in the 3rd column.
As shown in Fig. 4.

【table】

【table】

[Table] Comparative Examples 3 and 4 Microcrystalline cellulose A was carboxymethylated by the method described in Japanese Patent Publication No. 45-19438 using water as a solvent. That is, carboxymethylated microcrystalline cellulose was obtained in the same manner as in Example 1 described in the same publication, except that A was used instead of commercially available microcrystalline cellulose. That is, 45% sodium hydroxide aqueous solution was added to 600 g of A, and after stirring for 30 minutes while cooling to 5°C, 46% monochloroacetic acid aqueous solution was added at 0.55 and 1.20 g.
The amount of addition was changed and the reaction was carried out at 60°C for 1 hour. As the reaction progressed, the surface of the product became dissolved in the solvent. In particular, when 1.20% of monochloroacetic acid was added, the mixture became pasty. After cooling, it was neutralized with hydrochloric acid to release it, precipitated by adding methanol, centrifuged, sodium salt regenerated by adding sodium hydroxide, precipitated with methanol, and dried, but during the process, welding of particles was observed, and the raw material microcrystals. The particle shape was different from that of cellulose. Table 3 shows the results of measuring the degree of etherification and transparency of the product. Transparency was tested and quantified by the following method. Transparency A high-quality glass plate with a thickness of 2m/m is tightly attached to the bottom of a glass cylinder with a height of 250m/m, an inner diameter of 25m/m, and a thickness of 2m/m.
Place 15 parallel lines of 1m/m on a blank sheet of black paper. When a 1% aqueous suspension of a sample is placed in this Gallus cylinder and viewed from above, the height of the 1% aqueous suspension at which lines cannot be distinguished is defined as transparency. The better the sample dissolves in water, the greater the transparency.

【table】

[Table] Application Example 1 A pharmaceutical tablet compression test was conducted using A obtained in Production Example and the surface carboxymethylated microcrystalline cellulose obtained in Examples 1 and 2. These are used as excipients,
Table 4 shows the results of direct compression of a mixture of 49% ascorbic acid, 50% excipients, 0.5% magnesium stearate, and 0.5% talc under the same conditions.

[Table] However, the method for measuring hardness and abrasion is as follows. Hardness The hardness of each of the 20 tablets was measured using a Monsanto hardness meter, and the average value was taken. Abrasiveness Using a single-blade tablet abrasion tester with a diameter of 30 cm, 50 tablets of the sample were loaded and subjected to impact at 25 revolutions/min for 10 minutes. After impact, the tablets were taken out, broken and separated powder and small particles were removed by sieving, and the weight was measured, and the weight loss was expressed as a percentage of the original weight. Application Example 2 An emulsion stability test was conducted using A obtained in Production Example and the surface carboxymethylated microcrystalline cellulose obtained in Example-2. Prepare two sets (No. 1 and No. 2) of mixed slurry of 200 g of water, 10 g of sugar, and 15 g of skim milk powder.
20 g of surface carboxymethylated microcrystalline cellulose was added to 20 g of A, No. 2, and emulsified under the same conditions using a homomixer. The observation results after emulsification are listed in Table-5.

[Table] Application example 3 When 10 panelists conducted a test to taste the sensation of placing microcrystalline cellulose A and the surface carboxymethylated microcrystalline cellulose obtained in Example-2 on the tongue, all 10 panelists Microcrystalline cellulose A gave a somewhat rough feel and a foreign body sensation, whereas surface carboxymethylated microcrystalline cellulose had a smooth feel and did not give a foreign body sensation at all. Application Example 4 Next, bread to which these microcrystalline cellulose and derivatives were added was prepared. Preliminary flour (strong flour) 1400g, yeast 40g, yeast food 4g, water 700g were mixed and held at 26-27°C for 2 hours for primary fermentation. Next, the following powder was added to the above mixture and the mixture was prepared. Main flour (soft flour) 300g Additives (microcrystalline cellulose, etc.) 300g Sugar 100g Salt 50g Margarine 100g Dry milk 40g Water 600g After warming, divide into pieces that will make the desired bread loaf.
The mixture was aged at 27°C for 10 minutes, then placed in a baking mold and subjected to secondary fermentation at 37°C for 40 minutes. It was then heated in an oven at about 230°C for 45-70 minutes until baked. The additives are as follows. No. 1 No additives (600g of soft flour used in total) No. 2 Production example A No. 3 Commercially available microcrystalline cellulose (Avicel RC)
-N-81) No. 4 Surface carboxymethylated microcrystalline cellulose of Example-2 The baked appearance and tasting results are shown in Table-6.

[Table] ○: Good △: Slightly poor ×: Poor

[Brief explanation of the drawing]

The figure shows infrared absorption spectra of microcrystalline cellulose and carboxymethylated microcrystalline cellulose measured by the KB _r tablet method. Figure 1: Microcrystalline cellulose; Figure 2: carboxymethylated product; Figures 3 and 4: surface carboxymethylated product.

Claims (1)

[Claims] 1 When sodium carboxymethyl etherification of microcrystalline cellulose is carried out in an aliphatic alcohol/water mixed solvent, the weight ratio of water/aliphatic alcohol is in the range of 6/100 to 2/100, and the molar ratio of water/glucose is 3 to 5, and using monochloroacetic acid and solid sodium hydroxide as etherification agents, the particle surface of microcrystalline cellulose is treated with sodium carboxymethyl ether at a substitution degree of 0.05 to 0.8 per glucose unit. A method for producing a water-insoluble and water-dispersible microcrystalline cellulose derivative.